Package lucandra.dht

Source Code of lucandra.dht.RandomPartitioner

/**
* Copyright T Jake Luciani
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements.  See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership.  The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License.  You may obtain a copy of the License at
*
*     http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package lucandra.dht;

import static com.google.common.base.Charsets.UTF_8;

import java.nio.ByteBuffer;
import java.nio.charset.CharacterCodingException;

import lucandra.CassandraUtils;

import org.apache.cassandra.dht.BigIntegerToken;
import org.apache.cassandra.utils.ByteBufferUtil;
import org.apache.log4j.Logger;

/**
* A Random partitioner that's aware of our index hashing
*
*/
public class RandomPartitioner extends org.apache.cassandra.dht.RandomPartitioner
{

    public static Logger      logger         = Logger.getLogger(RandomPartitioner.class);
    private static final byte DELIMITER_BYTE = ":".getBytes()[0];

    public DecoratedKey<BigIntegerToken> decorateKey(ByteBuffer key)
    {
        return new DecoratedKey<BigIntegerToken>(getToken(key), key);
    }

    public DecoratedKey<BigIntegerToken> convertFromDiskFormat(ByteBuffer fromdisk)
    {
        // find the delimiter position
        int splitPoint = -1;
        for (int i = fromdisk.position(); i < fromdisk.limit(); i++)
        {
            if (fromdisk.get(i) == DELIMITER_BYTE)
            {
                splitPoint = i;
                break;
            }
        }
        assert splitPoint != -1;

       
        String token = null;
        try
        {
            token = ByteBufferUtil.string(fromdisk, fromdisk.position(), splitPoint - fromdisk.position(), UTF_8);
        }
        catch (CharacterCodingException e)
        {
            throw new RuntimeException(e);
        }
        ByteBuffer key = fromdisk.duplicate();
        key.position(splitPoint + 1);
        return new DecoratedKey<BigIntegerToken>(new BigIntegerToken(token), key);
    }

    public BigIntegerToken getToken(ByteBuffer key)
    {
        int length = key.remaining();

        if (length > 0)
        {
            boolean found = true;
            int firstNonChar = -1;
           
            //find our delimiter
            for (int i = key.position(); i < key.limit(); i++)
            {

                if (!Character.isDigit(key.get(i)))
                {
                    if (firstNonChar < 0)
                        firstNonChar = i;               
                }
                else
                {
                    if (firstNonChar >= 0)
                    {
                        found = false;
                        break;
                    }

                    continue;
                }

                // the rest is delimiter
                if ((i - firstNonChar) >= CassandraUtils.delimeterBytes.length
                        || key.get(i) != CassandraUtils.delimeterBytes[i - firstNonChar])
                {                   
                    found = false;
                    break;
                }
                else
                {

                    // Success
                    if ((i - firstNonChar) == (CassandraUtils.delimeterBytes.length - 1))
                        break;
                }
            }
           
            if(firstNonChar < 0)
                found = false;

            if (found)
            {
                String tokStr = null;
                try
                {
                    tokStr = ByteBufferUtil.string(key, key.position(), firstNonChar - key.position(), UTF_8);
                }
                catch (CharacterCodingException e)
                {
                    throw new RuntimeException(e);
                }
                //logger.info("Token hijacked:" + tokStr);

                return new BigIntegerToken(tokStr);
            }
           
        }

        return super.getToken(key);
    }

}
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